Laminated core and method for joining sheet metal parts into at least one laminated core

Abstract

A laminated core (2) and a method for joining sheet metal parts (4) to at least one laminated core (2) are presented. In order to obtain a laminated core (2) that is stable with respect to a cooling liquid, it is proposed to stack sheet metal parts (4) that have, at least locally, in particular over the entire surface, on their first hot-melt adhesive lacquer layer (5a), a relief (15) produced by embossing.

Description

Technical Field

[0001] The present invention relates to a laminated iron core and a method for joining metal plates into at least one laminated iron core, wherein metal plates having a first hot melt adhesive coating (especially baked enamel) on their first planar sides (preferably provided in a full-surface manner and / or thermally activated) are stacked and bonded into a laminated iron core by activating the hot melt adhesive coating. Background Technology

[0002] To manufacture laminated iron cores made of laminated metal sheets, it is known to stack the metal sheets and bond them together, i.e., by activating the thermoplastic adhesive layer between the metal sheets (EP3316457A1). Separation of the metal sheets is often achieved using a series of punching tools that cut the metal sheets from an electrical steel strip coated with thermoplastic adhesive. If the laminated iron core is cooled with a cooling liquid, the metal sheets need to be connected in a liquid-sealed manner to prevent leakage of liquid leaving or entering the laminated iron core. Disadvantageously, laminated iron cores requiring high liquid sealing for cooling under typically relatively high hydraulic pressures are difficult to manufacture. Summary of the Invention

[0003] Based on the lamination core described at the beginning, the purpose of this invention is to improve the material fit and connection between the metal plates, thereby obtaining a liquid-sealed lamination core that can withstand relatively high hydraulic pressure. Furthermore, the method should be easy to operate.

[0004] The present invention achieves the proposed objective through the features of claim 1.

[0005] By stacking metal plates that at least partially have embossed portions created by embossing at the first hot-melt adhesive layer, the material fit between the metal plates can be surprisingly significantly improved in terms of liquid-sealing connections. The embossed portions of the hot-melt adhesive layer reliably interrupt fluctuations in the thickness of the hot-melt adhesive layer and / or the flatness of the metal plates caused by the manufacturing process, preventing the formation of channel-like connections in the adhesive portion between the two metal plates. Furthermore, the embossed portions minimize closed air pockets and / or cavities, further improving the quality of the material fit connection and further reducing the risk of weak points. For example, the method according to the invention can thereby improve the sealing performance of the laminated core relative to coolant leakage.

[0006] If the relief portion is produced in a full-surface manner, the above-mentioned aspects can be improved, for example. However, it is sufficient for the relief portion to extend in a manner that closes around the cooling channels within the laminated iron core and / or closes along the outer surface of the laminated iron core.

[0007] Imprinting is also relatively simple to operate. For example, an embossed portion of the first hot-melt adhesive paint layer can be created using an imprinting tool, which only imprints the first hot-melt adhesive paint layer.

[0008] The laminated core according to the invention is therefore reliable and significantly more stable relative to leakage, even under relatively high liquid pressure.

[0009] Preferably, the relief portion has a recess and a relief structure raised from the recess, so as to stably minimize the opposing tolerances on the metal plates that need to be joined in a material-fit manner.

[0010] For example, a laminated iron core with an embossed structure having a structural height of at least 5µm and / or a structural height that is 1.1 to 5 times the thickness of the first hot-melt adhesive layer before embossing can be considered to have high stability. Preferably, the embossed structure has a structural height that is 1.5 to 3 times the thickness of the first hot-melt adhesive layer before embossing.

[0011] Alternatively or additionally, an embossed structure with a structural width of at least 50µm may be considered.

[0012] For example, the recess has a maximum recess width of at least 200 µm between two sequentially arranged relief structures, thus providing sufficient volume for extruding the relief structures even when small spacing is required between the individual metal sheets. This allows, for example, a compact laminated iron core with a relatively high magnetic content. In this case, a maximum recess width of at least 500 µm between two sequentially arranged relief structures can be advantageous, for example. Preferably, this refers to the maximum recess width observed on the longitudinal extension of the relief portion.

[0013] Preferably, the ratio of the structural height of the relief structure to the maximum width of the recess is less than 1:200, so as to smooth out even the smallest unevenness or defects at the bonding location. This further improves the pressure resistance of the laminated core. Preferably, this ratio is in the range of 1:20 to 1:120, for example, in the range of 1:20 to 1:50.

[0014] If the embossed portion forms a pattern with a regular structure, this pattern can further improve the uniformity of adhesion between the metal sheets. This is especially true when the pattern is a dot pattern, groove pattern, grid pattern, checkerboard pattern, waffle pattern, or honeycomb pattern. The pattern here can also be a pattern with a cyclical structure.

[0015] Preferably, each metal plate has a second hot-melt adhesive coating on its second planar side opposite to the first planar side. The embossed portion of the second hot-melt adhesive coating thus abuts against the first hot-melt adhesive coating, further improving the effectiveness of the embossed portion in forming a liquid-tight connection. For example, this can further improve the shear strength of the material fit connection between the metal plates, making the stacked core more leak-proof during rotation.

[0016] For example, the second hot melt adhesive layer is configured to be flat, which further improves the adhesion to the embossed first hot melt adhesive layer.

[0017] Alternatively or additionally, a second hot-melt adhesive coating layer may be considered to have a thickness ranging from 0.5 µm to less than 2 µm. In particular, a thickness of 1 µm to 1.5 µm for the second hot-melt adhesive coating layer may be sufficient.

[0018] For example, a particularly effective method for manufacturing laminated cores with liquid seals is to apply pressure (especially at least 2 N / mm²) to the metal sheets during and / or after stacking (especially during and / or after bonding). This allows the pressure-bearing embossed portions to reliably maintain dimensional tolerances, which further improves the stability of the laminated core relative to preferably higher hydraulic pressures. The pressure can be applied, for example, by a pressure device (e.g., a press). The pressure device can, for example, press against the stack and thus apply pressure to the metal sheets and the heat-fused adhesive coating.

[0019] Preferably, the first hot-melt adhesive coating layer is imprinted using an imprinting tool. For example, the imprinting tool is an imprinting roller and / or an imprinting punch, which can be simply arranged in a continuous process for manufacturing laminated iron cores.

[0020] When the embossing tool embosses the metal sheet at an embossing depth less than or equal to the thickness of the first hot melt adhesive layer, the sheet metal can be unaffected by the embossing.

[0021] If the hot melt adhesive layer is heated to a first temperature and then an embossed portion is created, the accuracy of creating the embossed portion can be improved, thereby further improving the accuracy of forming a strong bond.

[0022] Alternatively or additionally, the relief portion can be produced by an imprinting tool heated to a second temperature.

[0023] Preferably, the first temperature and / or the second temperature are greater than the glass transition temperature (Tg) of the hot melt adhesive and less than the drying temperature of the hot melt adhesive, thereby avoiding curing of the hot melt adhesive even in a relatively soft state and in the thus simplified imprinting.

[0024] The method can be further simplified if the metal sheet is separated from at least one electrical steel strip or sheet having (preferably arranged in a full-surface manner and / or capable of thermal activation) a first hot-melt adhesive coating layer on its first strip planar side.

[0025] Electrical steel strips or sheets may also have, for example, a second hot-melt adhesive coating layer (preferably provided across the entire surface and / or capable of thermal activation) on the second flat side of the strip. The first and / or second hot-melt adhesive coating layers may be, for example, baked enamel layers.

[0026] Preferably, an embossed portion is created on the first hot-melt adhesive coating layer before separating the metal sheets. This step can be performed, for example, before the sequential stamping tool used to separate the metal sheets, to further facilitate the operation of the method.

[0027] Furthermore, it is possible to consider that the laminated iron core has cooling channels for guiding the cooling liquid. These cooling channels can also extend entirely through the laminated iron core. Preferably, the cooling channels extending in the laminated iron core are elongated in the longitudinal direction of the laminated iron core, i.e., the axial direction. For example, notches in the metal plates of the laminated iron core define the cooling channels.

[0028] Alternatively or additionally, the outer periphery of the laminated core may also be locally formed with cooling channels for guiding the cooling liquid.

[0029] The present invention therefore aims to provide a liquid-sealed laminated iron core that can withstand even relatively high hydraulic pressure.

[0030] The present invention achieves the proposed objective through the features of claim 20.

[0031] If the bonding portions between the metal plates of the laminated iron core, formed by a first hot-melt adhesive layer or a second hot-melt adhesive layer, have at least partially embossed portions, the pressure resistance of the laminated iron core can be significantly improved. In particular, the embossed portions help to smooth and seal unevenness between the metal plates that are connected to each other and / or between the hot-melt adhesive layers that are connected to each other.

[0032] This is because the embossed portions on the laminated iron core can also be created after bonding (e.g., as a structured interface). Preferably, the bonded portions between the metal plates of the laminated iron core, formed by a first hot-melt adhesive layer or by a first hot-melt adhesive layer and a second hot-melt adhesive layer, at least partially have embossed portions configured as a structured interface. Attached Figure Description

[0033] The subject matter of the invention is described in detail with reference to exemplary embodiments in the accompanying drawings. Wherein: Figure 1An apparatus for performing the method according to the invention is shown.

[0034] Figure 2 It shows the use of according to Figure 1 A top view schematic diagram of the first hot-melt adhesive paint layer after being imprinted by the device. Figure 2a It shows Figure 2 A photograph of a portion of the hot melt adhesive paint that has been imprinted. Figure 3 It shows the use of Figure 1 An enlarged schematic diagram of the bonding method steps of the lamination method for the stacking of laminated iron cores implemented by the device. Figure 4a It shows Figure 1 An enlarged view of the imprinting process, and Figure 4b It shows Figure 2 Enlarged attached view of the elements of the embossed pattern. Detailed Implementation

[0035] according to Figure 1 An apparatus 1 is shown for manufacturing laminated iron cores 2, which are preferably used in electromagnetic components, such as motors. This method is also commonly referred to as a stacking method.

[0036] For this purpose, multiple metal plates 4 are separated from the electrical steel strip 3 (or, as not shown, from the electrical steel sheet) by means of device 1, for example. These metal plates 4 are often also referred to as laminations. The electrical steel strip 3 typically has an iron-silicon alloy. Furthermore, the electrical steel strip 3 is coated with a first thermosetting hot-melt adhesive layer 5a on the first flat side 3a and a second thermosetting hot-melt adhesive layer 5b on the second flat side 3b. More precisely, these hot-melt adhesive layers 5a, 5b are provided on both flat sides 3a, 3b in a full-surface manner, as shown in the example. Not shown is the first hot-melt adhesive layer 5a (as shown in the example, in a full-surface manner) on only one flat side 3a or 3b, which is used for tests V1, V3, V7 and V11 according to Table 2.

[0037] The first hot-melt adhesive layer 5a and / or the second hot-melt adhesive layer 5b, which are capable of being heat-cured and thus heat-activated, have, for example, an epoxy resin base. Such heat-curable and thus heat-activated hot-melt adhesive layers 5a, 5b, or hot-melt adhesive layers are also known as "baking paint." Preferably, the hot-melt adhesive is a bisphenol-based epoxy resin system having a curing agent (e.g., having a dicyandiamide group). In particular, the aforementioned hot-melt adhesive can be a bisphenol-A-epoxychloropropane resin system having dicyandiamide as a curing agent. This two-stage curing epoxy resin system is in state B on the electrical steel strip 3.

[0038] Therefore, partially cross-linked hot melt adhesives are reactive. By inputting heat, the hot melt adhesive in state B continues to react and can thus transform into a fully cross-linked state C, a process also known as "drying (Verbacken)". Typically, these partially cross-linked hot melt adhesive layers 5a, 5b have a thickness of several micrometers. The glass transition temperature Tg of the exemplary hot melt adhesive used, measured according to ISO 11357-2, is in the range of 65°C to 85°C. The drying temperature (Verbackungstemperatur) of the exemplary hot melt adhesive used is in the range of 180°C or greater. However, these characteristic values ​​for glass transition temperature and drying temperature can vary depending on the hot melt adhesive used.

[0039] With the help of stamping tool 7 (according to) Figure 1 Multiple metal sheets 4 are punched and separated from a coated electrical steel strip 3 using a series punching tool or a series composite tool. This punching can be, as generally mentioned, cutting, shearing, grooving, trimming, or dividing by stamping, but pressing out the metal sheets 4 is also possible. Preferably, the thickness of each metal sheet 4 is between 0.09 mm and 0.49 mm, and the thickness of each hot-melt adhesive coating layer 5a, 5b is, for example, between 2 µm and 12 µm.

[0040] Therefore, the metal sheet 4 separated from the single-sided coated electrical steel strip 1 has a first hot-melt adhesive paint layer 5a on its first planar side 4a. The metal sheet 4 separated from the double-sided coated electrical steel strip 1 has a first hot-melt adhesive paint layer 5a on its first planar side 4a and a second hot-melt adhesive paint layer 5b on its second planar side 4b.

[0041] In addition, from Figure 1 It can be seen that the stamping tool 7 cuts through multiple strokes 8 by the interaction of its upper tool 7a and its lower tool 7b. For this purpose, the stamping tool 7 has multiple stamping stages 9 and 10. The electrical steel strip 3 is pre-processed for blanking by the first punch 9a of the pre-processed stamping stage 9 located on the upper tool 7a, and then the metal sheet 4 is blanked (i.e. separated) from the electrical steel strip 3 by the second punch 10a of the second (and final) stamping stage 10 located on the upper tool 7a. For this purpose, the punches 9a and 10a interact with the corresponding dies 9b and 10b of the corresponding stamping stages 9 and 10 located on the lower tool 7b. This sequential cutting... Figure 1The main observation is that a portion 11 is separated from the electrical steel strip 3 during pre-processing stamping, so as to pre-process the electrical steel strip 3 to realize the cooling channel 14 in the laminated iron core 2. This allows notches to be created in the stamped metal sheet 4, which define the cooling channel 14 in the laminated iron core 2.

[0042] The metal sheet 4, punched out by the stamping stage 10, is pressed into the die 10b by the pressure P of the upper tool 7a or punch 10a, and then pressed into the stacking device 12 connected to the die 10b, whereby it is stacked. The stacking device 12 includes a shaft 13 with a core stop (Paketbremse) as known in the art, to hold the metal sheet 4 within the stacking device 12. Alternatively or additionally, opposing retainers (not shown in detail) may also be considered.

[0043] In this stacking apparatus 12, metal plates 4 are stacked vertically. The stacking apparatus 12 is actively heated for this purpose, for example by an electric heating device, which is not shown in detail. The hot melt adhesive layers 5a and 5b thus reach a third temperature, which is higher than the glass transition temperature Tg of the corresponding hot melt adhesive, i.e., reaching the third temperature at 100°C. The metal plates 4 are thus bonded into a laminated iron core 2, a process that can be either end-bonding or pre-bonding. For the latter, the laminated iron core 2 may undergo at least one additional curing step after leaving the stacking apparatus 12 to cure or dry the material mating joints between the metal plates 4. Furthermore, the stacking apparatus 12 can be rotated to form, for example, a laminated iron core 2 consisting of layers of metal plates 4 arranged side-by-side and stacked vertically, which is also not shown. All the stacked metal plates 4 are separated from the stacking device 12 as laminated iron cores 2, or are separated into laminated iron cores 2 at or after leaving the stacking device 12, which is not shown.

[0044] like Figure 1 As seen, the laminated iron core 2 has a through cooling channel 14, which is configured to guide cooling liquid, for example, for actively cooling the laminated iron core 2 during operation. In this embodiment, the cooling channel 14 extends longitudinally through the laminated iron core 2 and is defined by a metal plate 4, such as... Figure 3 The intermediate cooling channel 14 is not marked to scale. The laminated iron core 2 must therefore withstand hydraulic pressures, which can be very high during high-power operation, without leakage.

[0045] According to the invention, this is ensured by stacking metal plates 4 having at least partially (i.e., the entire surface in this embodiment) embossed portions 15 on their first hot-melt adhesive paint layer 5a, such as... Figure 2 and Figure 2a This can be observed in the process. For this purpose, the dedicated tool 1 has an impression roller as an impression tool 19, which creates an embossed portion 15 on the first hot-melt adhesive varnish layer 5a located on the electrical steel strip 3 before the electrical steel strip enters the stamping tool 7. However, it is also possible to create the embossed portion 15 on the corresponding first hot-melt adhesive varnish layer 5a located on the metal sheet 4, that is, after the metal sheet 4 has been separated; this point is not shown in detail. In this embodiment, the impression tool 19 only impressions the first hot-melt adhesive varnish 5a.

[0046] Table 1 shows a comparison of different types 1_A to 3_C of the embossed portion 15 of the first hot melt adhesive paint layer 5a with the prior art (SdT).

[0047]

[0048] Table 1: Different surfaces of the first hot melt adhesive coating layer 5a According to the relief sections from 1_A to 3_C, each has a recess 16 and a relief structure 17 raised from these recesses 16, such as Figure 2 , Figure 2a , Figure 4a and Figure 4b What I saw.

[0049] Because the embossing tool 19 has an embossing depth pt that is less than or equal to the thickness d1 of the first hot-melt adhesive paint layer 5a, the recess 16 can reach the plate of the metal sheet 4 within the first hot-melt adhesive paint layer 5a, for example... Figure 4a As shown in the figure. However, it is also possible that the metal plate 4 at the recess 16 is fully covered by the first hot-melt adhesive paint layer 5a.

[0050] According to Table 1, from 1_A to 3_C, the structural height of the embossed structure 17 varies from 1.1 to 5 times the thickness d1 of the first hot-melt adhesive layer 5a before embossing. The embossed structures 17 from 1_A to 3_C also have a structural width sbr of at least 50µm. Furthermore, the recess 16 has a maximum recess width kp of at least 200µm between two sequentially arranged embossed structures 17.

[0051] Therefore, according to the present invention, the embossed portion 15 from 1_A to 3_C interrupts the fluctuation S in the thickness d2 of the second hot-melt adhesive paint layer 5b caused by the manufacturing process, such as Figure 3 This can be observed in the image. Furthermore, these relief portions 15 from 1_A to 3_C according to the invention can also smooth out unevenness in the metal sheet caused by the manufacturing process, a point not shown in detail.

[0052] This reliably prevents the formation of channel-like connections in the adhesive portions between the metal plates 4. Therefore, even under relatively high hydraulic pressures, there is no need to worry about coolant leakage, as observed in tests V3 to V12 according to the invention, as shown in Table 2.

[0053]

[0054] Table 2: Different stress tests For the laminated iron cores manufactured according to Table 2 from tests V1 to V14, electrical steel sheets with a thickness of 0.25 mm were used. These sheets were either coated with a first hot-melt adhesive layer 5a (thickness d1) on one side, or coated with a first hot-melt adhesive layer 5a (thickness d1) on the first planar side 3a and a first hot-melt adhesive layer 5b (thickness d2) on the second planar side 3b. Rembrandtin's EB549 was used as the hot-melt adhesive layers 5a and 5b. It is a thermally activated epoxy resin-based hot-melt adhesive.

[0055] All laminated iron cores 2 manufactured according to tests V1 to V14 were manufactured using apparatus 1 with identical geometric specifications. Furthermore, all laminated iron cores 2 manufactured according to tests V1 to V14 were bonded for 2 hours at 200°C and a pressure P of 3 N / mm². The distance between the cooling channel and the outer contour of the laminated iron core 2 was 2 mm.

[0056] According to Table 2, significantly higher pressure resistance can be observed in the laminated cores (V3 to V14) according to the present invention, that is, the maximum liquid pressure is 100 times higher than the maximum liquid pressure of the prior art according to test V1. Even if the paint layer of the laminated core V2 is thickened under pressure, the value reached is still less than one-fiftieth of the maximum liquid pressure of the laminated core 2 according to the present invention according to tests V3 to V14.

[0057] In addition, especially in Figure 3 It can be observed that the thickness d1 of the first hot melt adhesive layer 5a on each separated metal plate 4 is greater than the thickness d2 of the flat second hot melt adhesive layer 5b.

[0058] The embossed portion 15 is set in the first hot-melt adhesive paint layer 5a in a particularly precise conformal manner. This is especially advantageous when the ratio of the structural height sbr of the embossed structure 17 to the maximum recess width kp of the recess 16 is relatively small (less than 1:200), as seen in all tests. Particularly high sealing performance, as well as sealing of extremely small defects or uneven areas, can be achieved with a ratio ranging from 1:20 to 1:50, as shown in tests 1_A, 2_A, 3_A, and 3_B.

[0059] Heating the first hot-melt adhesive layer 5a to a first temperature t1 via a radiation source 18 (e.g., an infrared source) before the impression roller 16 is advantageous for this precise conformation setting. This first temperature is 80°C, which is greater than the glass transition temperature (Tg) of the hot-melt adhesive layer 5a and less than its drying temperature. Furthermore, the impression roller 16 is also heated to the same second temperature t2, i.e., 80°C, which further improves the uniformity of the imprinted relief portion 15. This allows for the particularly precise and fine formation, for example, of patterns with a uniform and cyclical structure, i.e., honeycomb patterns, such as... Figure 2 This honeycomb pattern was observed in [the text].

[0060] Figure 2 It can also be observed that the relief section 15 completely surrounds the extension of the cooling channel 14. This allows for a particularly good seal.

[0061] However, it is also possible to consider forming cooling channels for guiding the cooling liquid locally on the outer surface 18 of the iron core. Figure 1 The diagram only schematically illustrates that the outer periphery 18 of the core is the outer cover or outer surface of the laminated core 2. For example, the laminated core 2 can be the stator of an electric motor, whose (stator) core outer periphery 18 is cooled (stator cover cooling). The core outer periphery 18 thus only partially defines a cooling channel, more precisely, this cooling channel is formed by the core outer periphery 18 and other parts of the motor (not shown). In this case, the laminated core 2 is also particularly sealed relative to the infiltration of coolant.

[0062] Alternatively, it is also possible to provide at least a portion of the embossed portion 15 on the bonded laminated iron core 1, thereby making it detectable. This is especially important when it is necessary to prevent the hot melt adhesive from being squeezed out during bonding due to the use of relatively low pressure P. For example, the embossed portion 15 between the metal plates 4 can be configured as a structured interface. The structured interface can appear, for example, between the first hot melt adhesive layer 5a and the metal plate 4, or even between the first and second hot melt adhesive layers.

[0063] Generally, "particularly" can be translated as "more particularly" in English. Features preceded by "particularly" are considered optional features that can be omitted and do not impose limitations, such as on claims. The same applies to "preferably," which is translated as "preferably" in English.

Claims

1. A method for joining metal plates (4) into at least one laminated iron core (2), wherein, Metal plates (4) are stacked, each metal plate having a first hot-melt adhesive paint layer (5a) on its first planar side (4a). Preferably, the first hot-melt adhesive paint layer is provided on the entire surface and / or is heat-activated. In particular, the first hot-melt adhesive paint layer is a baked enamel finish. The metal plates are bonded into the laminated iron core (2) by activating the hot melt adhesive paint layer (5a). Its features are, The metal plates (4) are stacked, and the metal plates have at least partially embossed portions (15) formed by embossing on the first hot melt adhesive paint layer (5a) of the metal plates. In particular, the metal plates have embossed portions (15) formed by embossing on the entire surface of the first hot melt adhesive paint layer (5a) of the metal plates.

2. The method according to claim 1, characterized in that, The relief portion (15) has a recess (16) and a relief structure (17) raised from the recess (16).

3. The method according to claim 2, characterized in that, The structural height (dr) of the embossed structure (17) is at least 5µm and / or the structural height (dr) of the embossed structure (17) is in the range of 1.1 to 5 times the thickness (d1) of the first hot melt adhesive layer (5a) before the first hot melt adhesive layer is imprinted. In particular, the structural height (dr) of the embossed structure (17) is at least 5µm and / or the structural height (dr) of the embossed structure (17) is in the range of 1.5 to 3 times the thickness (d1) of the first hot melt adhesive layer (5a) before the first hot melt adhesive layer is imprinted.

4. The method according to claim 2 or 3, characterized in that, The relief structure (17) has a structural width (sbr) of at least 50µm.

5. The method according to claim 2, 3, or 4, characterized in that, The maximum recess width (kp) of the recess (16) between the two sequentially arranged relief structures (17) is at least 200µm, and in particular, the maximum recess width (kp) of the recess (16) between the two sequentially arranged relief structures (17) is at least 500µm.

6. The method according to any one of claims 2 to 5, characterized in that, The ratio of the structural height (sbr) of the relief structure (17) to the maximum recess width (kp) of the recess (16) is less than 1:

200. In particular, the ratio of the structural height (sbr) of the relief structure (17) to the maximum recess width (kp) of the recess (16) is in the range of 1:20 to 1:

120. For example, the ratio of the structural height (sbr) of the relief structure (17) to the maximum recess width (kp) of the recess (16) is in the range of 1:20 to 1:

50.

7. The method according to any one of claims 1 to 6, characterized in that, The relief portion (15) forms a pattern with a regular structure. In particular, the relief portion (15) forms a pattern with a cyclic structure. In particular, the pattern is a dot pattern, a groove pattern, a grid pattern, a checkerboard pattern, a waffle pattern, or a honeycomb pattern.

8. The method according to any one of claims 1 to 7, characterized in that, Each metal plate (4) has a second hot melt adhesive paint layer (5b) on a second planar side (4b) opposite to the first planar side (4a) of the metal plate.

9. The method according to claim 8, characterized in that, The second hot melt adhesive paint layer (5b) is configured to be flat and / or the second hot melt adhesive paint layer (5b) has a layer thickness (d2) in the range of 0.5µm to less than 2µm, in particular, the second hot melt adhesive paint layer (5b) has a layer thickness (d2) in the range of 1µm to less than 1.5µm.

10. The method according to any one of claims 1 to 9, characterized in that, Pressure (p) is applied to the metal plate (4) during and / or after the metal plate (4) is stacked. In particular, pressure (P) is applied to the metal plate (4) during and / or after the metal plate (4) is bonded. In particular, the pressure is at least 2 N / mm².

11. The method according to any one of claims 1 to 10, characterized in that, The first hot melt adhesive paint layer (5a) is imprinted by an imprinting tool (19), specifically by an imprinting roller and / or an imprinting punch, and / or the imprinting tool (19) imprints the first hot melt adhesive paint layer (5a) with an imprinting depth (pt) less than or equal to the layer thickness (d1) of the first hot melt adhesive paint layer (5a).

12. The method according to any one of claims 1 to 11, characterized in that, The first hot melt adhesive paint layer (5a) has a layer thickness (d2) greater than or equal to 2µm. In particular, the first hot melt adhesive paint layer (5a) has a layer thickness (d2) in the range of 2µm to 12µm.

13. The method according to any one of claims 1 to 12, characterized in that, The hot melt adhesive paint layer is heated to a first temperature (t1) and the embossed portion (15) is subsequently produced, and / or the embossed portion (15) is produced by an imprinting tool (19) heated to a second temperature (t2).

14. The method according to claim 13, characterized in that, The first temperature (t1) and / or the second temperature (t2) are greater than the glass transition temperature (Tg) of the hot melt adhesive and less than the drying temperature of the hot melt adhesive.

15. The method according to any one of claims 1 to 14, characterized in that, The metal plate (4) is separated from at least one electrical steel strip or electrical steel sheet (3), which has the first hot melt adhesive paint layer (5a) on the first strip plane side (3a) of the electrical steel strip or electrical steel sheet. Preferably, the first hot melt adhesive paint layer is provided in a full-surface manner and / or is heat-activated. In particular, the first hot melt adhesive paint layer is a baked paint layer.

16. The method according to claim 15, characterized in that, The electrical steel strip or sheet (3) has a second hot melt adhesive paint layer (5b) on the second strip plane side (3b) of the electrical steel strip or sheet. Preferably, the second hot melt adhesive paint layer is provided in a full-surface manner and / or is heat-activated. In particular, the second hot melt adhesive paint layer is a baked paint layer.

17. The method according to claim 15 or 16, characterized in that, The relief portion (15) is created on the first hot melt adhesive paint layer (5b) before the metal plate (4) is separated. In particular, the relief portion (15) is created upstream of the sequential stamping tool used to separate the metal plate (4).

18. The method according to any one of claims 1 to 17, characterized in that, The laminated iron core (2) has a cooling channel (14) for guiding cooling liquid. In particular, the cooling channel extends through the laminated iron core, and / or the outer periphery (18) of the laminated iron core partially forms a cooling channel for guiding cooling liquid.

19. The method according to claim 18, characterized in that, An embossed portion (15) is created that extends in a manner that closes around the cooling channel (14) located within the laminated iron core (2).

20. A laminated iron core manufactured using the method according to any one of claims 1 to 19, characterized in that, The bonding portion between the metal plate (4) of the laminated iron core (1), formed by the first hot melt adhesive paint layer (5a) or by the first hot melt adhesive paint layer (5a) and the second hot melt adhesive paint layer (5b), has at least a partial relief portion (15).

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